As usual, the SDK can be used alongside of other SDKs, so you can use this in a production environment as long as your apps still target Windows 10 version 1809. It's only officially supported by Visual Studio 2017 and greater, and you can install it on any supported version of Windows 10.

There isn't a lot that's changed in this build, although there's a new Fluent Design feature called Luminosity. This is part of AcrylicBrush and it's to make sure that shadows don't appear behind acrylic surfaces unless there's a cutout.

Here's the changelog:

In this Preview SDK we’ll be adding a blend mode to the effect graph of the AcrylicBrush called Luminosity. This blend mode will ensure that shadows don’t appear behind acrylic surfaces without a cutout. We will also be exposing a LuminosityBlendOpacity API available for tweaking that allows for more AcrylicBrush customization.

By default, for those that have not specified any LuminosityBlendOpacity on their AcrylicBrushes, we have implemented some logic to ensure that the Acrylic will look as similar as it can to current 1809 acrylics. Please note that we will be updating our default brushes to account for this recipe change.